Method of making articles having a polygonal cross section



NOV. 14, 1933. R WILCOX 1,934,752

METHOD OF MAKING ARTICLES HAVING A POLYGONAL CROSS SECTION METHOD OF MAKING ARTICLES HAVING A POLYGONAL CROSS SECTION Filed Aug. 24, 1932 2 Sheets-Sheet 2 IN V EN TOR.

50 f/ D 67 #www BY all@ ATTORNEY Patented Nov. 14, 7191?3 PATENT OFFICE METHOD OF MAKING ARTICLES HAVING AA POLYGONAL CROSS SECTION Richard Lester Wilcox, Waterbury, Conn., as'

signor to The Waterbury Farrel Foundry and Machine Company, Waterbury, Conn., a corporation of Connecticut Application August 24, 1932. Serial No. 630,235

12 Claims.

This invention relates to means and method for making articles having a polygonal cross section, particularly bolts, nuts, rivets, screws and the like.

It is the object of this invention, among other things, to produce articles of the character mentioned without loss of metal, by arranging for and controlling the ow of the metal so that the finished product may be of very high quality and with thecorners of the polygon sharp and even and with one or more chamfered faces.

'Ihe invention is illustrated and describedas applied to the manufacture of an article having a hexagonal cross section but is not limited,- however, to such shape.

Referring to the drawings, in which like characters of reference indicate like parts in the several figures: I

Figure 1 is a transverse sectional view of a set of dies, punches and associatedparts of a header, upsetting machine or the like;

Figure 2 is a group view of a bolt blank, showing the various forms it assumes during its fabrication;

Figure 3 is a transverse sectional view of some of the parts, taken generally upon line 4-4 of Figure 5;

Figure 4 is a similar view with some of the parts in other relative positions;

Figure 5 is a cross sectional view of the parts shown in Figures 3 and 4, taken substantially upon line 5-5 of Figure 4;

Figure 6 is an enlarged fragmentary view of a bolt, screw or the like, having a head that is hexagonal in cross section, at that stage of its formation after being subjected to pressure by the radial dies, and designed to have a chamfer at the top of the head;

Figure 7 is a fragmentary view of a blank with a head formed so that the finished article may have a chamfer on both top and bottom thereof;

Figure 8 is an elevation of the same blank after it has been subjected to the pressure of the uting dies;

Figure 9 is a plan view of the blank shown in Figure 8;

Figure 10 is a fragmentary view of a completed article having a chamfer on the top and bottom thereof;

Figure 11 is a fragmentary elevation of a blank for an article that is substantially square in cross section, after4 being subjected to the pressure of the iluting dies;

Figure 12 is a plan view of the blank shown in Figure 11;

Figure 13 is a fragmentary view of a coinpleted article with a chamfer upon one side of the head thereof which is substantially-square in cross section;

Figures 14 and 15 are views of a hexagon and square nut, respectively, produced by the means and method herein disclosed; and

Figures 16, 17 and 18 are fragmentary views showing the application of the means and method herein disclosed in the production of a socalled carriage bolt having a head substantially square in cross section and a mushroom top.

In the formation of an article with a polygonal cross section it is customary to first form the same cylindrical in shape with a diameter substantially the same as the distance between the at faces of the subsequently formed polygon. Pressure applied to the cylindrical shape causes a substantially uniform radial flow of the metal outwardly in every direction.

Little or no radial ow of metal is in fact required at the center of the flat faces, while at the ends of these faces (the corners), a very substantial ow of metal is required. The result is unsatisfactory because the outward radial flow of metal opposite the flat faces is retarded by the walls in the opening of the forming die before the metal opposite the corners engages these walls. As a consequence, the metal opposite the flat-faces overflows such walls, forming a ash or iin before the corners fill out. This flash or n is objectionable, particularly if the article requires a chamfer, and is removed in a subsequent turning or trimming operation. Therefore, the article cannot be completed in the forming die. Another objection is the fact that any article in such positioning to completely ll the opening of the die, especially at the corners, has a tendency to break the die and in any event, to shorten its life, owing to unequal strains upon the walls thereof.

If the cylindrical shape has a diameter more nearly approaching that of the distance across the corners of the polygon a subsequent operation is required, similar to that of drawing through a die, to obtain the desired finish. This also creates a flash or fin that must be removed in a subsequent turning operation. In either method there is a loss of metal.

Another method frequently used which has many of the objections of those above described, including the loss of material, is to make the cylindrical shape with a diameter larger than the distance across the corners of the nished polygon. In such case the walls of the cylinder are cut or sheared in a trimming machine or the like to produce the desired polygonal shape. As a rule the sides so trimmed are not smooth but marred by scoring or gouging marks, which are removed usually by a subsequent planishing operation. All of these practices which require trimming, either to shear the sides or to remove the fiash or iin, waste a substantial amount of material, and the cost of production thereof is increased owing to the additional machinery and labor required.

In this invention the cylindrical head of the blank has a diameter that more nearly approximates the distance across the corners of the polygonal head than across the dat sides or faces.

The cylindrical blank is subjected to lateral pressure at several places around its perimeter, producing a plurality of depressions and forming a uted blank. The shape of the coned cylindrical blank and the shape and depth of the depressions therein are such that the metal will ow to'complete a finished polygonal article in an upsetting die as the result of pressure upon the end thereof, with the sides or faces of the polygon and the corners filled out to the desired form.

As presented to the die to obtain its nal polygonal form, the several points about the fluted blank having the largest diameter are opposite the corners of the die opening and the portions having the smallest diameter, that is, at the bottom of the depressions, are opposite the flat sides or faces. Fluting the blank enables the corners to be filled and completed before the center of the flat faces. This prevents an overflow of metal from the die and produces a chamfer because the metal around the conev of the cylindrical head has an unrestrained flow. Such shaping of the blank and flow of the metal insures the production of a chamfered article having a polygonal cross section without subsequent turning or trimming operations and without loss of material.

In the drawings, 10 designates a die holder of an upsetting machine or the like, within which are a plurality of dies 11, 12, 13 and 14, each abutting against a backing plate 15.

Opposite the die holder is a punch holder 16, in which ismounted the punches 17, 18 and 19, all of which abut against a backing plate 20. In each of the dies are knockout pins 21, 22 and 23.

The wire from which the article is produced is fed as a rod length 24 through the die 11 and the projecting portion is cut off by a knife 25.

All the mechanism above described, except the 4die 13 and punch 18 are now known in the art and constitute no part of the present invention.

In practice, the die holder 10 is held rigid and the punch holder 16 is moved toward and away therefrom by means well known in the art and constitute no part of the present invention.

By reason of this motion the punches engage the blank in line therewith, and in conjunction with the co-operating dies, perform operations thereof. When the punch holder 16 is distant from the die holder 10, the cut of! portion of the rod length 24, now the blank 26, is transferred into line with the punch 17 and die 12. Subsequent movement oi the punch holder 16 toward the die holder 10 causes the blank to be projected into the die 12 against the knockout pin 21 and upsets a portion of the blank into a cylindrical form, substantially as shown in Figures 1 and 2. The top and bottom faces of this cylindrical portion are coned, the angle on the under face being less than that of the top face if a chamfer is to be formed on one side only, and substantially equal hexagonal in cross section, there are six of these for a chamfer upon both sides, as shownr in Figure 7.

The collapsible die 13 is'constructed with a body member 27, having an opening 28 there-- through of plural diameters, in the walls of the small diameter of which are a plurality of radial slots 29. The rear walls of these slots are at an angle to the axis of the opening 28. As the die herein shown isdesigned to produce `an article slots, one for each flat face of the finished product. A greater or less number of finished faces will correspondingly increase or reduce the number of required slots. Movable in each slot is a fiuting-die 30. These are formed with a rounded nose 31 that is substantially parallel with vthe corresponding nose of each of the other dies when assembled, a cam face 32 which rides against the angular wall of a slot 29, a cam face 33, and stop shoulders 41.

It is preferable that the fiuting dies 30 should not contact with each other, but that an open space be left therebetween, substantially as shown in Figure 5, whereby to accommodate flow of the metal.

'Movably mounted within the backing plate 15 and an opening in the body member 27 is a sleeve 34 having a cone head 35, the angle of which is substantially the same as that of the cam faces 33, which contact therewith. 'I'he diameter of 105 the head 35 of the sleeve is substantially the same as that of the smaller diameter portion of the opening 28, within which it is slidably mounted. The punch 18 has a recess 36 in its rear face enclosing a spring 37 which bears against the head 110 38 of the pressure pin 39. A

The blank 26 with its cylindrical head is presented by suitable transfer mechanism in line with the collapsible die 13 and punch 18, the parts then being in the position substantially as shown in Figure 3, the upper edges of the fluting dies 30 being substantially flush with the top of a plate 40 secured to the body member 27 and the stop shoulders 41 against the underside thereof which limit the position of the dies in one direction.

As the punch holder 16 moves toward the die holder 10 the end of the pressure pin 39 engages the top of the cylindrical head and projects the shank of the blark into the opening in the sleeve 34. The underside of the head isnow against the top of the sleeve 34 in the position substantially as shown in Figure 3. The sleeve 34 thus serves as a platform and a centering guide for the blanks. Continued movement of the punch 1 holder brings the pressure face of the punch 18 against the top of all of the iluting dies 30, which by reason thereof are moved axially within the body member 27. The iluting dies under this action move inwardly toward the axis of the blank by reason of the engagement of the cam faces 32 of the dies with the angular walls of the sleeve.

. Endwise pressure is also applied to the sleeve 34 through the engagement of the cam' faces 33 on the fluting dies with the conical head of 1Q the sleeve. During this movement of the punch holder, the pressure pin 39 recedes within the punch 18 against the tension of the spring 37 and the nose of each of the fluting dies 30 is forced against and into the walls of the cylinu! drical blank, forming a depression in the outer wall thereof, which continues to grow in depth until the termination of a predetermined limit of movement of the punch 18. This inward movement of the fluting dies 30 imparts an end- 1.

wise movement to the sleeve 34 which thereby moves away from the blank, now tightly held between the fluting dies 30. At one extreme position of the parts, the top of the conical head of the sleeve 34 is distant from the underside of the head, substantially as shown in Figure 4, leaving an open space therebetween. Pressure against the outer wall` of the cylindrical blank elongates the same so that it is considerably higher after this operation than before. Moving the sleeve 34 away from the head of the blank permits the flow of the metal substantially parallel with the shank on the underside of the head without being restrained by the sleeve. As the spring 37 is relatively light there is practically no resistance to the ow of the metal upwardly at the top of the head. The punch 18 is withdrawn as the punch holder 16 moves away from the die holder 10 and at the latter portion of such withdrawal carries with it the pin 39 by reason of the engagement of the head 38 against the bottom of the recess 36.

When the blank has been thus released from endwise pressure by the punch 18, the knockout pin 22 advances and applies pressure to the blank to eject it from the die. During such action the uting dies move with the blank until the shoulders 41 thereon engage the plate 40, freeing the friction thereof upon the cam faces 32. The spring 42 moves the sleeve 34 and by reason of its cam engagement with the uting dies 30 the latter are moved outwardly releasing the blank from the iluting dies. The continued movement of the knockout pin 22 completely ejects the blank from the die. The dies and sleeve are now ready for the next succeeding blank. The depressions as formed by the fluting dies are designated 44 and the curvatures ofthe bottom thereof are determined by the curvature of the nose 31 of the fluting dies.

These in turn are shaped so that the bottom of the depressions will ilow outwardly under a common pressure on this and other parts of the head, and the flow of the metal Will produce the nal form of article without formation of a flash or fin, and with a suitable chamfer lupon one or-both sides as desired. After the blank is ejected from the die it is carried by transfer mechanism into line with the die 14 and punch 19. A-t the next forward movement of the punch holder 16 the punch 19 projects the blank into the die 14 and die block 43. Pressure now applied causesthe metal in the uted blank to ow outwardly until it engages the inner walls of the opening in the die 14, which in cross section is the same as that of the cross sectional shape of the finished article, in this case, hexagonal in form.

I Pressure applied to the top of the conical fluted blank by the punch 19 diminishes its height with a resulting outward ow of the metal thereof which rst engages the corners of the opening in the die 14 and then flows toward the center of the flat faces by reason of the shape and depth of the depressions. IThe walls and corners of the opening in the die 14 are thereby filled and an article is produced with a polygonal cross section Without the formation of a flash or fin and a chamfer which is formed without engaging a limiting face.

If the chamfer is to be on both sides of the blank, the same is coned so that the two faces 45 and 46 are at substantiallythe same angle with respect to the axis thereof, with a band por- ,therein being substantially preserved.l Pressure tion 47 substantially centrally located therebetween.

` The axial ilow of the metal caused by the flut-- ing dies 30 moving into and toward the axis of the blank, compensates for the inward displacement thereof. The angles of the faces 45 and 46 after such flow being greater with respect to the top face of the blank, the shape ofthe circle applied by the punch 19 upon the top face produces the desired shape in cross section in the manner above described, except that a chamfer is formed at boththe top and bottom oi' the article. Figs. '1, 8,` 9 and 10 illustrate the article in its several forms, in the production of a bolt having such chamfer upon both ends of the head thereof. g

Figs. 16, 17 and 18 illustrate a common form of carriage bolt, in which, during its formation, the upset portion of the blank 50 that forms the polygonal portion 49 of the head is distant from the end of the blank, as shown in Fig. 16. That portion between the upset portion and the end forms the mushroom top 48, substantially as shown in Fig. 18.

While the drawings heretofore referred to relate to the production of bolts, screws, rivets and the like, the invention is equally adapted for the production of like articles, such as nuts. An illustration of an hexagonal nut produced by the means and method herein disclosed, is shown in Fig. 14, and a square nut in Fig. 15. The only difference so far as this invention is concerned between a bolt as an article and that of thenut being that the former has a shank and the latter has an opening therethrough.

By the method and means herein. disclosed, which latter is one of the many forms that may be utilized for the purpose, it is possible tol form, While the metal is cold, an article having a polygonal cross section, and of such high character and quality that it does not require subsequent operations thereon.

Within the scope of the appended claims, the details of the embodiment of the invention as herein disclosed may be varied or altered Without departing from the spirit thereof.

What I claim isz- 1. A method for making metal articles having a polygonal cross section, comprising the forming of a cold blank having a cylindrical wall, applying pressure to the cylindrical wall thereof at spaced intervals, whereby depressions are formed in the' perimeter thereof, and thereafter applying axial pressure to the blank whereby the metal is caused to flow outwardly to its final form while the blank remains in its initial cold state and the metal necessary to ll out the depressions being derived in part from that portion of the blank between the depressions and the end of the blank.

2. A method for making metal articles having a polygonal cross section comprising the forming of a cold blank having a cylindrical wall, applying pressure to the cylindrical wall thereof at spaced intervals, whereby depressions are formed at substantially that portion thereof that will be the sides or faces thereof, and thereafter applying axial pressure while the blank remains in its initial cold state and the metal necessary to fill out. the depressions being derived in part from that portion of the blank between the depressions and the end of the blank.

3. A method for making metal articles under pressure and having a polygonal cross section while cold, the final form of which is determined applying pressure to the cylindrical wall thereof at spaced intervals whereby depressions ,are

l formed in the perimeter thereof of less' height than the blank, placing the blank, sov shaped in the die, with those portions having the largest diameter opposite the corners of the said die opening and applying pressure to the blank while so positioned, whereby the metal is caused to flow radially outwardly, eliminating the depressions, and the walls of which become the faces or sides of the article and the metal necessary to fill out the depressions being derived in part from that portion of the blank between the depressions and the end of the blank. Y

4. A method for making metal articles having a polygonal cross section while cold, comprising the shaping of a blank having a cylindrical wall with a plurality of depressions in the said cylindrical wall of less height than the blank, then placing such blank in a conforming opening of substantially the same shape as the exterior of the article, with the depressions opposite the at sides or walls of the opening and the points therebetween opposite the corners of said opening and finally applying pressure to the end of the blank whereby the metal thereof is caused to flow outwardly and fill the said opening, the metal necessary to illl out the depressions being derived in part from that portion of the blank between Vthe depressions and the end of the blank.

5. A method for making metal articles having a polygonal cross section while cold, comprising the shaping of a blank with a plurality of concave depressions in a cylindrical wall thereof of less height than the blank, then placing such blank in a conforming opening of substantially the same shape as the exterior of the article, with the depressions opposite the fiat sides or walls of the opening and the points therebetween opposite the corners of said opening and finally applying pressure to the end of the blank, whereby the metal will flow radially in all directions and without axial flow after the metal has reached the limits ofthe radial flow the metal necessary to fill out the depressions being derived in part from that portion of the blank between the depressions and the end of the blank.

6. A method for making metal articles having a polygonal cross section while cold, comprising the shaping of a blank with a plurality of depressions in the outer wall thereof and a cone on one face, then placing such blank in a conforming opening of substantially the same shape as the exterior of the article, with the depressions opposite the flat sides or walls of the opening and the points therebetween opposite the comers of said opening and finally applying pressure to the end of the blank whereby the metal thereof is caused to flow outwardly and fill the said opening with a chamfer on its end face.

7. A method for making metal articles having a polygonal cross section while cold, comprising the forming of a coned blank having a cylindrical wall, then by lateral pressure forming a plurality of depressions in the cylindrical wall thereof and thereby elongating the article, and then placing such blank in an opening of substantially the same shape as the exterior of the article, with the depressions opposite the flat sides of the opening, and nally applying endwise pressure to the blank, whereby its height is reduced and the metal thereof caused to flow radially out- Lasers wardly, and filling the opening and forming a chamfer upon one face of the article.

8. A method for making metal articles having a polygonal cross section while cold, comprising the forming of a blank having a cylindrical wall with coned top and bottom surface, then by lateral pressure forming a plurality of depressions in the cylindrical wall thereof and thereby elongating the article and then placing such blank in an opening of substantially the same shape as the exterior of the article, with the depressions opposite the flat sides of the opening and finally applying endwise pressure to the blank, whereby its height isreduced and the metal thereof caused to ow radially outwardly, and filling the opening and forming a charnfer upon one face of the article and at upon the opposite face.

9. A method for making metal articles having a Vpolygonal cross section while cold, comprising the forming of a coned blank having a cylindrical wall, then by lateral pressure forming a plurality of depressions in the cylindrical wall thereof, thereby elongating the article in both directions which elongation is unrestricted and then placing such blank in an opening of substantially the same shape a's the exterior of the article with the depressions opposite the sides of the opening, and finally applying endwise pressure to the blank, whereby its height is reduced and the metal thereof caused to ilow radially outwardly and fill the opening, one face of the article being chamfered and the other face flat.

10. A method for making metal articles having a polygonal cross section while cold, comprising the forming of a blank having a cylindrical wall with faces at opposite ends thereof, inclined relatively to the axis of the blank, as in a cone, and then by lateral pressure forming a plurality of depressions in the cylindrical wall thereof and thereby elongating the article, which is least upon that side of the blank having the face with the lesser angle and then placing the blank in an opening of substantially the same shape as the exterior of the article, with the depressions opposite the flat sides thereof and then applying endwise pressure to the blank, whereby its height is reduced and the metal thereof caused to ilow radially, fill the opening and that vface having the greater angle becoming in part a chamfer upon one side of the article.

11. A method for making metal articles having a polygonal cross section while cold, comprising the forming of a blank having, a cylindrical wall with conical faces at opposite ends thereof inclined relatively to the axis of the blank as in a cone, and then by lateral pressure forming a plurality of depressions in the cylindrical wall thereof, and thereby elongating the article,

and then placing the blank in an opening substantially the same shape as the exterior of the article and with the depressions opposite the at sides thereof and then applying endwise pressure to the blank whereby its height is reduced and the metal thereof caused to ilow radially, fill the opening, and form a chamfer upon each side of the article.

12. A method for forming metal articles having a polygonal cross section while cold, comprising the forming of a blank having a cylindrical wall with a central band portion and be` veled ends, which taper from said band portion to the opposite ends of thearticle in substantially the same angle with respect to the whereby its height is reduced and the metal thereo( caused to ow radially, filling the said opening except at the adjacent opposite faces thereof which are formed into a chamfer at both ends of the article.

RICHARD LESTER WILCOX. 

